Improvement in Bias Stability of IGZO TFT With Etching Stop Structure by UV Irradiation Treatment of Active Layer Island

Cheng-Chao Pan,Ji-Feng Shi,Jian-Hua Zhang,Xiang Sun,Long-Long Chen,Shi-Bo Yang,Xi-Feng Li

doi:10.1109/jeds.2020.2983251

Cheng-Chao Pan, Ji-Feng Shi + Show 5 more

Open Access

https://doi.org/10.1109/jeds.2020.2983251

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Abstract

In this paper, the effect of ultraviolet (UV) irradiation treatment of active layer IGZO on the bias stability of amorphous IGZO thin film transistor with etch stop (ES) structure is studied. Along with the increase in UV irradiation time, the surface of the IGZO film becomes smoother. An appropriate UV irradiation treatment cannot only improve the bias stress stability but also suppress the lump behavior generated by light illumination. The devices with irradiation time of 1 min exhibits an excellent properties with the field effect mobility of 15.07 cm2/V·s, subthreshold swing of 0.2 V/dec, and all bias stress less than 0.2 V including NIBS and PIBS. However, a relative long UV treatment would result in deteriorating the bias stability of devices. The fact implies that the reasonable UV irradiation treatment on the active layer island before depositing the ES layer is advantageous for improving the stability of the a-IGZO TFT device.

Highlights

Since IGZO TFT was firstly reported [1], it has become the most promising driving technique of TFT backplane for display due to high transmission and high mobility [2]–[5]
The fact shows that UV irradiation treatment maybe improve IGZO film surface which were favorable for suppressing leakage current caused by surface roughness and enhance the charge carrier mobility in the channel
In this paper, the stability of an a-IGZO TFT device with an etch stop layer (ES) structure was investigated for applying different UV irradiation time to the IGZO pattern

Summary

Introduction

Since IGZO TFT was firstly reported [1], it has become the most promising driving technique of TFT backplane for display due to high transmission and high mobility [2]–[5]. The research on the effect of post-treatment before the ES layer deposition, after the active layer patterning, on the device performance and stability of the a-IGZO TFT is still less.

Results

Conclusion